PSI - Issue 5

L. ALEXANDRESCU et al. / Procedia Structural Integrity 5 (2017) 675–682 Laurentia Alexandrescu / Structural Integrity Procedia 00 (2017) 000 – 000

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requirements of polymer nanocomposites is optimized shock resistance, for use in heavy blow conditions. PA value is 2.5 KJ/m 2 and GPP01-4,11 (compound PA/PP-g-MA/PP). All nanocomposites tested have increased values compared to the control sample PA and GPP01, ranging between 6,12 and 7.43 KJ/m 2 . Increased values were obtained for samples GPP7 (PA/PP-g-MA/PP/GO-0.5% GO) – 6.91 KJ/m 2 and GPP8 (PA/PP-g-MA/PP/GO-1% GO) – 7.43 KJ/m 2 . Graphene oxide concentrations higher than 1% lead to decreases in shock resistance values similarly to tensile strength values. This leads to the conclusion that percentages in the 0.1-1% range lead to maximum values of physical mechanical parameters. - In order to establish the technological parameters for processing GPP6-GPP10 polymeric architectures in finished products, tests were carried out to determine the melt flow index at a temperatures of 230°C and a pressure of 5 kg. The analysis of the obtained values (Table 2) show an increased flow compared to GPP01 (41,9 g / 10min) for the samples: GPP6 (0.1% GO) -53,3 g / 10min, GPP7 (0.5% GO) 54,7 g / 10 min and GPP8 (1% G) 62,4 g / 10 min. The other samples, with concentrations above 1% GO in the composite, GPP9-2.5% GO and G10-5% GO have flow values below the control sample value, which demonstrates that higher graphite concentrations in the nanocomposite have a positive influence on the flow of the material in the injection process, the value is GPP9 (2,5% GO) 69 g / 10 min and GPP10 (5% GO) 76 g / 10 min. - SEM image of the cross section of the fracture obtained from polyamide elastomer (PA), presented in Figure 3, emphasize a lamellar structure. On the other hand, the SEM images of cross sections of the fracture obtained from the other four samples (GPP01, GPP6, GPP8 and GPP10), shown in the Figures 4-7, in which the nanocomposites with rates differ from GO, have completely different aspects: they show a biphasic type morphology consisting in spheroid particles distributed within a matrix with less evident lamellar morphology. The number of particles increases directly with the amount of GO of the nanocompound.

Figure 3 SEM images from sample PA

Figure 4 SEM images from sample GPP01

Figure 5 SEM images from sample GPP6

Figure 6 SEM images from sample GPP8

Figure 7 SEM images from sample GPP10

- FT-IT spectroscopy. IR spectrum represent the radiant energy absorption curve in the IR domain by the sample molecule, depending on the wave length or radiation frequency. The infrared domain of the electromagnetic radiation is between 0.8 and 200 μm. IR domain for usual organic chemistry is between 2.5 and 25 μm. The structural determinations were carried out on an IR molecular absorption spectrometer with double beam, in the range of 4000 600 cm -1 , using 4200 FT-IR equipped with ATR diamond crystal and sapphire head. The solid state samples were set in the ATR and the equipment recorded the transmittance spectra of the sample and then compared it with the background spectra previously recorded. The recorded spectra of the samples were compared with the pure elastomer